Cancer is a common illness so it is not unusual to have more than one family member with different types of cancer. However, in some cases families may be predisposed to certain types of cancer.

About 15 to 20 per cent of cases of ovarian cancer occur because of a genetic cause - a mutation in one or more genes known to increase the risk of ovarian cancer that has been passed on from your mother or father. Some types of ovarian cancer are more likely to be caused by a mutation in a gene than others.

Genes are chemical instructions made from DNA, which tell the cells in our bodies how to work. Every cell in our body contains genes that determine and regulate our body’s functions, growth and appearance. Each person has two copies of each gene, one inherited from their mother and one from their father.

In general, our genes enable our cells to function normally. However, sometimes the genes that were inherited have small changes, known as alterations or mutations. If one of our genes is mutated this can result in an increased risk of developing different illnesses.

A person with a gene mutation has a 50/50 (one in two) chance of passing it on to each of his or her children.

‘Hereditary’ means the passing on of specific characteristics in your DNA from one generation to another – in this case, passing on a mutation in a gene. The term ‘familial’ means something that occurs or tends to occur in families.

‘Familial cancer’ or ‘hereditary cancer’ is a cancer which has developed as a result of carrying a mutation in a gene. Throughout these web pages, we refer to it as hereditary ovarian cancer.

There are a number of considerations to think about if you find out you have hereditary ovarian cancer. Firstly, there’s the impact on you – some hereditary ovarian cancers also increase your risk of developing other cancers, including breast cancer and so you would need to consider ways to manage this increased risk. It may also have some implications for the treatment of your ovarian cancer. Secondly, there could be an impact on family members who may also have inherited the gene mutation which could put them at increased risk of ovarian and breast cancer. This guide talks through these considerations and gives more information on each.

Women diagnosed with non-mucinous ovarian cancer in the UK, irrespective of family history, should be offered genetic testing for mutations in their BRCA1 and BRCA2 genes. Over 90 per cent of ovarian cancers diagnosed are non-mucinous. Some women may not be eligible, due to the specific type of cancer they have or the age at which they first developed ovarian cancer, but it is important all women discuss genetic testing with their GP or clinician to find out if testing is appropriate.

“I had no previous family history of cancer, on either side of my family, other than an uncle who died of a bowel cancer. I didn’t even know about possible familial risk until I attended a Target Ovarian Cancer Being Together day, after a question was asked to the expert panel.” Shani

It’s also important to note that mutations in genes such as BRCA1 and BRCA2 can occur in any family; however, they are more common in some communities. For example, members of the Ashkenazi Jewish population are approximately 10 times more likely to have a mutated BRCA1 or BRCA2 gene, and so are at greater risk of developing hereditary ovarian and/or breast cancer than people from the general population.

“My family is from Ashkenazi Jewish background, and many of my aunts and cousins have had either cancer or preventative surgery. Despite this, it’s still not widely talked about which contributes to lack of awareness of the gene.”Diane

“I discovered I had the BRCA2 gene mutation almost by chance. I was young, fit and healthy when I was diagnosed with breast cancer. I questioned why but was told it was probably just bad luck. Eight years later, I was diagnosed with ovarian cancer. The consultants said there was probably genetic involvement and I received counselling about the BRCA gene. What came out when completing my family history form was that at least four members of my father’s family had died of related cancers.” Adele